Growth forecasts are certainly bullish: Citigroup forecasts Vladivostok's gross gaming revenue, or GGR, will climb to $1.7 billion by 2020, from an estimated $410 million in 2016, and it expects Manila's GGR will rise at a 16 percent compound annual growth rate to $5.8 billion by 2020.

That's relatively small compared with mature market Macau, with around $55 billion in GGR expected this year, according to Citigroup's data. But the bank is bullish on the three frontier gaming market leaders – Summit Ascent, Melco Crown Philippines and Nagacorp – for their projects' close proximity to China, favorable visa policies for mainland tourists and strong arrival growth.

These bullish forecasts for frontier casinos really depend on "how much money people have to be playing around with and how much do people want to get money out of China," said Freya Beamish, an economist at Lombard Street Research.

She noted that due to restrictions on the China's capital account, gambling has become one of the ways people move money out of the country.

"It won't necessarily happen in a successful way," she said. "Investment is very weak and private consumption is by default the strongest thing in the economy," she added, noting she expects economic growth may slow to around 5 percent this year as well as in years ahead, compared with an official target of around 7.5 percent.

"You're going to have a similar amount, or less, of private consumption, but private consumption is leading growth," she said.

Of course, frontier casino markets may be able to profit even if the hoped-for Chinese tourists don't materialize.

Gaming in Asia is underpenetrated, Macquarie said in a report in December, citing a growing number of high-net-worth individuals and a growing acceptance of integrated casino resorts as a form of entertainment.

For example, it believes the Philippines' domestic market is also promising and its forecast for gaming growth there may be more bullish than Citigroup's; Macquarie forecasts the gaming market may grow to $4.8 billion by 2017.

"Not only is the Philippines seeing strong economic growth, but the demographics are also supportive of higher disposable incomes and greater growth in consumption expenditure," it said, although it noted competition in the market is intense.